The present invention relates to a method of constructing phased array ultrasound transducers of the type used for medical imaging and to medical ultrasound transducers produced by the inventive method.
As is well known in the medical ultrasound imaging art, there are various types of ultrasound scanners. These include mechanical scanners, such as rotating and oscillating scanners, and electronic scanners, such as linear array transducers, and phased array transducers. Ultrasound transducers are typically comprised of a piezoelectric material, such as a lead-zirconate-titanate (PZT) crystal, which is made to oscillate by the imposition of a signal. Phased array transducers are typically comprised of a small bar of a piezoelectric material which is cut into a number of elements which are pulsed in sequence, with appropriate delays, whereby they send out electronically steered waves of ultrasound energy. Typically, phased array transducers are quite small dimensionally. Accordingly, they are very difficult to construct, and a major portion of the expense associated with manufacturing a phased array scanhead is associated with the labor required to construct the scanhead.
An additional expense associated with the manufacture of phased array transducers is that they require separate signal handling channels for each of the elements in the array. In view of the fact that each channel requires a number of components, and the further fact that a phased array transducer often includes at least 32 channels, the expense of producing the electronics for each channel is large. Accordingly, it is quite expensive to manufacture a phased array scanhead and then to find, after manufacture, that it is inoperative for some reason.